As the information society progresses in these years, it increases the technical importance on the display medium, the hard copying, and so on. However, the paper, which has been used as a medium for transporting the information over the years, has very high portability and storage stability. An in these days, a display medium has been developed that is like a paper and provided with a memory.
As the display medium mentioned above, the electronic paper is proposed (Published Japanese patent application No. 10-171620) and also the electronic paper file wherein a plurality of such electronic papers are formed in a notebook-like form (Published Japanese translation of PCT application, No. 11-502950). In addition, as a recording material of the display medium, various rewritable recording mediums are studied (Pages 209 to 251 of “Japan Hardcopy'99—The Collected Papers” published by The Imaging Society in Japan).
The electronic paper file has been improved in order to support the needs that, instead of printing letters and images on papers, the electronic paper is an information terminal to store letters and images as electronic information copiable and editable freely and it is configured like a book or a notebook that is familiar to us heretofore.
In other words, the electronic paper file is different from a conventional display device as represented by CRT display or LCD display and has a portable and notebook-like configuration. And unlike the portable information terminal (PDA: Portable digital Assistant, and notebook personal computer) and so on, the electronic paper file comprises a plurality of display units.
Now, some of the conventional portable information terminals are provided with a communication function, and by using such communication function those terminals can exchange information mutually in anywhere. The method of exchanging information is sending and receiving files, exchanging message in real time by means of communication tool (Chat), and the like. In case where an information terminal provided with the communication function is given to each participator of a conference and an image data regarding the conference data is transmitted to the information terminal, each participator can read the conference data on his information terminal without using the whiteboard.
However, the portable information terminal is provided with only one display in A4 size at most due to the portability performance. Therefore, the display has to be divided in order to browse the data consisting of plural documents or to input more data referring to a specific document, which may be an inconvenient environment.
When the user exchanges data by means of the communication tool or uses the information terminal at the conference, the display screen displays a common data (screen). Accordingly, it is very hard for each user to obtain spaces for inputting or displaying his information for which the user makes a note or browses a different page for his own benefit.
This is a reason that the above information terminal cannot substitute for the book or notebook with superior facility for browsing even though the terminal can store characters and images as electronic information along with involving the portability.
Therefore, the invention has an object to provide an electronic paper file with the merits of the book or notebook, wherein a problem regarding the displaying that appears on the information terminal particularly at the communication.